feat(physics): port retail projectile integration

Add a pure Core projectile driver for retail clock quanta, final-state acceleration, 50-unit velocity clamping, world-space angular integration, full-3D AlignPath, and oriented Setup-local sphere sweeps. Preserve exact success versus set_frame-only failure semantics, independent Contact/OnWalkable state, and full-cell identity across all landblock directions.

Port OBJECTINFO::missile_ignore with explicit weenie/creature metadata, remove the invented transition-step cap, retain PathClipped without arming PerfectClip, and keep authoritative target identity optional. Add malformed-shape/clock, thin-wall, terrain, target-exclusion, frame-spike, failure-state, and boundary conformance coverage.

Retire TS-2 and synchronize the architecture, milestones, roadmap, research oracle, and durable physics memory.

Co-Authored-By: Codex <noreply@openai.com>

tests/AcDream.Core.Tests/Physics/MissileCollisionRulesTests.cs

@@ -0,0 +1,94 @@
+using AcDream.Core.Physics;
+using Xunit;
+
+namespace AcDream.Core.Tests.Physics;
+
+/// <summary>
+/// Conformance table for retail <c>OBJECTINFO::missile_ignore</c>
+/// (<c>0x0050CEB0</c>). These tests deliberately separate "has a weenie"
+/// from "is a creature" because the retail branches do.
+/// </summary>
+public sealed class MissileCollisionRulesTests
+{
+    private const uint Target = 0x1111u;
+    private const uint Other = 0x2222u;
+
+    private static ObjectInfo Missile(uint targetId = 0) => new()
+    {
+        MoverPhysicsState = PhysicsStateFlags.Missile,
+        TargetId = targetId,
+    };
+
+    [Fact]
+    public void OtherMissile_IsAlwaysIgnored_EvenWhenDesignated()
+    {
+        var mover = Missile(Target);
+        Assert.True(mover.MissileIgnore(
+            Target,
+            (uint)PhysicsStateFlags.Missile,
+            EntityCollisionFlags.HasWeenie));
+    }
+
+    [Fact]
+    public void NonMissileMover_DoesNotUseMissileExemptions()
+    {
+        var mover = new ObjectInfo();
+        Assert.False(mover.MissileIgnore(
+            Other,
+            (uint)PhysicsStateFlags.Ethereal,
+            EntityCollisionFlags.HasWeenie | EntityCollisionFlags.IsCreature));
+    }
+
+    [Fact]
+    public void DesignatedTarget_IsNeverIgnoredByLaterBranches()
+    {
+        var mover = Missile(Target);
+        Assert.False(mover.MissileIgnore(
+            Target,
+            (uint)PhysicsStateFlags.Ethereal,
+            EntityCollisionFlags.HasWeenie | EntityCollisionFlags.IsCreature));
+    }
+
+    [Theory]
+    [InlineData(true, true)]
+    [InlineData(false, false)]
+    public void EtherealTarget_RequiresWeenieMetadata(bool hasWeenie, bool ignored)
+    {
+        var flags = hasWeenie
+            ? EntityCollisionFlags.HasWeenie
+            : EntityCollisionFlags.None;
+
+        Assert.Equal(ignored, Missile().MissileIgnore(
+            Other,
+            (uint)PhysicsStateFlags.Ethereal,
+            flags));
+    }
+
+    [Fact]
+    public void KnownTarget_IgnoresOtherCreatures()
+    {
+        var mover = Missile(Target);
+        Assert.True(mover.MissileIgnore(
+            Other,
+            0u,
+            EntityCollisionFlags.HasWeenie | EntityCollisionFlags.IsCreature));
+    }
+
+    [Fact]
+    public void UnknownTarget_DoesNotIgnoreCreatures()
+    {
+        Assert.False(Missile().MissileIgnore(
+            Other,
+            0u,
+            EntityCollisionFlags.HasWeenie | EntityCollisionFlags.IsCreature));
+    }
+
+    [Fact]
+    public void KnownTarget_DoesNotIgnoreNonCreatureWeenie()
+    {
+        Assert.False(Missile(Target).MissileIgnore(
+            Other,
+            0u,
+            EntityCollisionFlags.HasWeenie));
+    }
+}